This invention generally relates to passenger conveyor systems. More particularly, this invention relates to passenger conveyor systems having parallel straight-aways moving in opposite directions with moving drive members.
Conventional passenger conveyors, such as moving walkways or escalators, typically include a chain of steps that travel in a loop to provide a continuous movement along a specified path. Typical arrangements include an arrangement where the steps pass along the exposed moving pathway and then move beneath the exposed pathway as they travel a return path of the loop hidden beneath the exposed moving steps. With such arrangements, separate loops of steps are required to provide motion in different directions. Additionally, each loop requires its own drive assembly to provide the necessary movement.
Designers of passenger conveyor systems face several challenges including space constraints, system expense and safety concerns. Passenger conveyor systems need to fit within packaging constraints dictated by building structures or layouts.
A significant amount of space typically is required for the drive assemblies associated with the individual chains of steps along each loop of the passenger conveyor pathways. Those skilled in the art have long been striving to develop conveyor arrangements that do not require as much space as conventional systems. Minimizing the space required for a conveyor system typically must be balanced with the need to provide adequate system performance (i.e., load carrying capacity) and minimizing system expenses.
System expenses typically are caused by the number of parts and the complexity of the components. Minimizing duplication of parts is always a goal to make passenger conveyor systems more economical.
Another issue presented by escalator style passenger conveyor systems is the possibility for objects to become caught between the moving steps and the stationary system structure. This possibility is greatest at transition zones such as near landings.
Various attempts have been made at minimizing or eliminating the possibility for objects to become caught at the interface between moving parts in a passenger conveyor system. Stationary skirt panels do not eliminate relative motion although they do cover some of the conveyor components. Moveable skirt panels have been proposed, but not always successfully implemented in the marketplace. An example proposal is shown in U.S. Pat. No. 4,470,497, which has a two-piece skirt guard arrangement that has not proven successful in the marketplace.
There is a need for an arrangement that minimizes space requirement, reduces expenses and guards against the possibility for objects to become caught or entrapped at the interface of moving parts in a passenger conveyor system. This invention addresses that need in a manner that is superior to previously attempted arrangements. Moreover, this invention makes it possible to utilize a racetrack style loop of steps that eliminates duplication of parts and presents substantial cost and space savings.
In general terms, this invention is a racetrack style passenger conveyor system. A system designed according to this invention includes a plurality of pallets each having a step surface that is adapted to support at least one foot of at least one passenger. The pallets travel along a continuous path that includes two straight sections moving in different directions and a turn around section at each end of the straight sections.
A plurality of first drive members are associated with the first lateral edges of the pallets. The first drive members are connected together to be moveable relative to each other, which facilitates the pallets traveling around the turnaround sections of the continuous path.
A plurality of second drive members are associated with the second lateral edges of the pallets. The second drive members include a releasable connection between adjacent second drive members that is operative to maintain adjacent second drive members together as the corresponding pallets travel along the straight sections and to release the adjacent drive members from each other when the corresponding pallets travel along the turnaround sections.
Another aspect of a conveyor system designed according to this invention includes a drive mechanism that engages at least the first plurality of drive members so that a motive force provided by the drive mechanism propels the pallets along the path. In one example, the drive mechanism also engages the plurality of second drive members.
Another aspect of this invention is providing a first plurality of drive members along an inner side of the path followed by the steps. The first plurality of drive members preferably remain connected together throughout the travel along the entire path. Another plurality of drive members are associated with an outer side of the loop. The outer side drive members preferably remain connected together along straight sections of the path. The outer side drive members preferably disconnect from each other to allow spacing between outer edges of adjacent pallets so that the pallets can travel along the turnaround sections of the path.